Could you please explain the difference for me? Afaik public domain is meant to be free as well. The reason for it being free might be different from actual freeware but isn't the end result the same?

Could be rights of distribution. You (personal you) can distribute a public domain item, but you may not be able to distribute a freeware item (like Ultima IV before coming to GOG for example).

I think the problem isn't public domain, but freeware. For example a developer/publisher can make a game freeware, but only for downloads from his own site (I know several freeware developers that don't want their games anywhere else, because they want to stay in control of updates, patches, etc.) or they make the game freeware for personal use, but don't allow commercial distribution. That's why most freeware games still come with an EULA. or a readme file.

Thank you. Every day you (meaning "me") learn something new :)

Public domain = copyright is either expired, has never existed, or the creator has willingly chosen to give up any rights for the work.

Freeware = the work is copyrighted just as much as any commercial distribution, but the copyright holder has given the work for free distribution under certain conditions. These conditions can be selected servers (such as free on GOG, for example) or selected uses (such as free for academic use and education), or something else.

The most obvious difference is that you can rip anything from PD sources and use it as you like, and you don't even need to credit the original creators (although it would be nice if you did). If you try to rip something from freeware though, you are violating all kinds of laws and can be held responsible for doing so, ending up going to court and paying fines and all that.